Air bleed system for hydraulic table reciprocating mechanism



May 13, 1952 C. G. FLYGARE AIR BLEED SYSTEM FOR HYDRAULIC TABLE RECIPROCATING MECHANISM Filed March 10, 1951 CA PL 57MAUEJ Patented May 13, 1952 AIR BLEED SYSTEM FOR HYDRAULIC TABLE RECIPROCATING MECHANISM Carl G. Flygare, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application March 10, 1951, Serial N 0. 214,936

2 Claims.

The invention relates to machine tools and more particularly to a hydraulically operated table reciprocating mechanism.

One object of the invention is to provide a simple and thoroughly practical hydraulically operated table reciprocating mechanism. Another object of the invention is to provide a hydraulic table reciprocating mechanism, in which the cylinder reciprocates with the table, with a bleeder system whereby air may be readily bled from the table cylinder during reciprocatory movement thereof. Another object is to provide a bleeder system for a reciprocable table cylinder for bleeding air from the cylinder without the necessity of providing flexible hose connections therefor. Another object of the invention is to provide a bleeder system in which independent bleeder ports are provided in the piston for bleeding air from the cylinder and passing it through a centrally located tube within the hollow piston rod. Another object of the invention is to provide a bleeder system for a hydraulic table reciprocating mechanism in which a pair of pistons are provided having hollow piston rods to connect the pistons with the base of the machine in which independent bleeder ports are provided in the pistons adjacent to the uppermost part of the cylinder so that air may be bled therefrom. and passed through bleeder tubes centrally located within the hollow piston rods. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

One embodiment of the invention has been illustrated in the drawing, in which:

Fig. 1 is a hydraulic diagram of a hydraulically operated table reciprocating mechanism;

Fig. 2 is a fragmentary sectional View, on an enlarged scale, of one of the bleeder valves for the hydraulic system; and

Fig. 3 is a fragmentary sectional view on an enlarged scale, of one of the pistons, showing the independent pressure and bleeder ports therein.

The improved hydraulically operated table reciprocating mechanism has been illustrated in the drawing comprising a longitudinally reciprocable table II] which is arranged to slide longitudinally on suitable ways (not shown) on a machine base 20. The table I is arranged so that it may be reciprocated longitudinally by and automatically controlled by a hydraulically operated reciprocating mechanism comprising a cylinder II the opposite ends of which are supported by brackets l2 and I3 mounted on the underside of the table I0. The cylinder II contains a pair of spaced pistons l4 and I5. The pistons I4 and I5 are connected by hollow piston rods 16 and I1 respectively with brackets l8 and I9 which are fixedly mounted on opposite ends of the machine base 20.

The bracket I8 is provided with an upwardly extending portion having a U-shaped slot 2| in its upper end to receive a reduced end portion of the piston-rod I6. A pair of collars or nuts 22 and 23 are screw threaded onto a threaded portion 24 formed on the left-hand end of the piston rod [6. By manipulation of the collars 22 and 23, the piston rod I6 may be readily clamped to the bracket l 8 in the desired adjusted position.

Similarly the bracket I9 is provided. with an upwardly extending portion having a U-shaped slot 25 to receive a reduced end portion of the hollow piston rod II. A pair of collars or nuts 26 and 21 are screw threaded onto a reduced threaded portion 28 of the piston rod [1. By manipulation of the collars 26 and 21, the piston rod I! may be readily clamped to the bracket I9 in the desired adjusted position. If desired the table 10 together with the cylinder l l and pistons I4 and I5 may be readily removed from the machine by loosening the collars 22 and 23 and the collars 26 and 21.

A fluid pressure system is provided for supplying fluid under pressure to the table cylinder II comprising a motor driven fluid pump 30 which draws fluid through a pipe 3| from a reservoir 32 which may be located either within or outside of the base 20. The pump 30 forces fluid under pressure through a pipe 33 to a manually operable start and stop valve 34. A relief valve 35 is connected in the pipe line 33 to facilitate maintaining the desired operating pressure within the hydraulic system. The relief valve 35 serves to exhaust excess fluid under pressure through a pipe 36 into the reservoir 32.

The start-stop valve 34 is a piston type valve controlled by a manually operable lever 31. The pipe 33 also supplies fluid under pressure to a table actuated reversing valve 39 which is actuated by a lever 40 by means of table dogs (not shown) carried by the table [0. The reversing valve 39 serves to convey fluid under pressure through a pipe 45 into a central aperture 46 Within the hollow piston rod I 6, or through a pipe 41 into a passage 48 formed within the hollow piston rod ll. A fluid actuated by-pass valve 50 is provided to facilitate Icy-passing fluid between opposite ends of the cylinder II when the parts are in condition for a manual traversing movement of the table In. As illustrated in Fig. 1,. the bypass valve 50 is a piston type valve having a valve chamber 5| which is connected by a pair of pipes 52 and 53 with pipes 45 and 4! respectively. In this position of the by-pass valve fluid within 3 a cylinder chamber 3 at the left-hand end of the cylinder ll may pass through a port 55,

through the central passage 48 in the piston rod it, through the pipe 52, through the valve chamher 5!, the pipe 53, the central passage 48 in the piston rod- 3? and through a port 55 into a cylinder chamber 5? at the right-hand end of the cylinder ll. It will be readily apparent that in this position of the by-pass 59 the table it may be readily traversed Without the necessity of overcoming fluid pressure in the system, since it may readily by-pass between the cylinder chambers Ed and 5?.

When it is desired to start atable reciprocating movement, the control lever 31 may be rockedin a counter-clockwise direction to shift the valve parts so that fluid under pressure in the pipe 33 will pass through a chamber 58 in the start-stop valve 3d and through a pipe 59 into an end chamber 5t formed in the right-hand end of the bypass valve 52. Pressure within the chamber 88 serves to overcome the compression of a spring 6| to shift the valve 58 so that the valve piston 52 closes ofi the ports at the ends of the pipes 52 and 53 thereby preventing further icy-passing of fluid-between the cylinder chambers 5d and 5?. At the same time fluid under pressure in the pipe 33 passes through a valve chamber 65 in the reversing valve 39 and through the pipe 45, through the passage 66, the port 55 into the cylinder chamber Ed to move the cylinder II and the table it toward the left. During this movement of the table fluid within the cylinder chamber 5i may exhaust through the port 56, the passage it, the pipe l-l into a valve chamber 63 in the reversing valve 39. Fluid exhausting through the valve chamber (it passes through a pipe 61, through a chamber 68 formed in the start-stop valve 3d, and out through a pipe 6d, and a throttle valve '58 and through a pipe ll into the pipe 35 to exhaust into the reservoir 32. The setting of the throttle valve it determines the rate of movement of the table i ll. 5

Similarly when the table ctuated lever d6 is shifted into a reverse position, the reversing valve parts are shifted so that fluid under pressure passes through the pipe ii, through thepassage t8, the port EB into the cylinder chamber 5? to start movement of the cylinder H and table It toward the right.

In order to attain the main object of this invention, a suitable bleeder system is provided whereby air leaking into the hydraulic system and the cylinder ii may be readily bled therefrom when desired. It is preferable to arrange the bleeder system so that air may be. bled from the cylinder ll manually through suitable connections and retur to the reservoir 32. In the preferred "construction, bleeder ports and F6 are provided in the upper portions of the pistons is and 45 respectively so, that air accumulating within the cylinder it rises to the uppermost part of the cylinder and may readily be withdrawn therefrom. The bleeder ports 15 and 16 are connected through bleeder tubes H and 18 extending through the hollow apertures 46 and d3 4 jacent to the top portion of the cylinder ll may be readily exhausted through the valves 8! and 82 and passed through pipes 85 and 86 which returns the air laden fluid to the reservoir 32. It will be readily apparent from the foregoing disclosure that the bleeder valves BI and 82 may be normally closed and opened as desired to bleed air from the cylinder I l. If desired the valves 81 and 82 may be partially opened so that during the reciprocatory movement of the table 10 and cylinder l- I a continuous bleeding of air and fluid from the upper portion of the cylinder l I may be obtained.

It will thus be'seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore setforth, or shown in theaccompanying drawing, is to be interpreted as illustrative and not in a limiting sense.

in the hollow piston rods l6 and [1 respectively.

baseto support the other end of said piston rod,

a reversing valve to convey fluid under pressure through said rod into the cylinder, a fluid reservoir, means including a pump to supply fluid under, pressure, and a bleeder system therefor including a bleeder port in said piston adjacent V to the upper portion of said cylinder, a bleeder tube connected therewith and extending through said hollow piston rod, a manually operable bleeder valve at the outer end of said tube, and a pipe connecting said bleeder valve with the reservoir'whereby air and fluid bled from the cylinder is returned to the reservoir.

2. In a machine tool having a base, a. longitudinally reciprocable table thereon, a hydraulic cylinder fixedly mounted on said table, a pair of spaced pistons withinisaid cylinder, a. pair of hollow piston rods connected with said pistons, brackets on opposite ends of said basev to support the outer ends of said piston rods, areversing valveto convey fluid under pressure through said rods into the cylinder, a reservoir, means-including a pump to supply fluid under pressure, and a bleeder system therefor including a bleeder port in each of said pistons adjacent to the upper portion of said cylinder, a separatebleeder tube connected with each of said ports and exe tending; through said hollow piston rods, a man- REFERENCES CITED 7 The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,890,244 Barrett et al Dec. 6,1932 1,938,772 Ernst et. al Dec.112, 1933 2,037,262

7 Parsons -Apr. 14, 1936 

